LIGHTS:
What's red, green and white and can be safely seen in the dark?
A properly lit boat.

Seth says, "When is a boat invisible but still visible?
When it's dark and you know what the lights mean. Boat knowledge leads to boating safely."

Hi, I'm Seth!
Know how lights are positioned on a boat and you will know which way other boats are moving at night.
It's night and you see moving boat lights. Are you about to meet it head-on, pass the other boat or is it crossing in front of you?